Electrical connector assembly and method



1967 R. TRAVIS ETAL 3,296,577

ELECTRICAL CONNECTOR ASSEMBLY AND METHOD Filed Oct. 21, 1964 L a wrence1?. no wk and Robert A. Ra mey k wwa United States Patent 3,296,577ELECTRICAL CONNECTGR ASSEMBLY AND METHOD Lawrence R. Travis and RobertA. Ramey, Monroeville, Pa., assignors to Westinghouse ElectricCorporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct.21, 1964, Ser. No. 405,341 6 Claims. (Cl. 339-275) The present inventionrelates to electrical connector assemblies, and more particularly toelectrical connector assemblies for soldering together an electricalconductor and a female type of connector.

Numerous electrical connector assemblies have been devised for solderingtogether an electrical conductor, usually a wire having a circularcross-section, and a female type of connector contact or terminal. Oneof the most common systems is that of inserting a wire into a solder cuptype of female connector which has a relatively large cross-sectioncompared to that of the wire and then applying solder and heat to theassembly to complete the connection. The difliculties with this systemare: the solder provides the complete connection between the wire andthe female conductor, the use of the solder cup type of connectorintroduces a large amount of solder around the wire which may createvoids or pockets in the solder and thereby affect the electricalconductivity of the connection, and a relatively long time is requiredfor making such a connection because of the number of steps involved.Moreover, if a large number of connections are to be made within alimited area difficulty may be encountered in completing the array usingthe above method. Another frequently used connector assembly is that ofa solderless or pressure type of connection in which the conductor andconnector are secured together mechanically, for example by crimping, orby placing a band about the conductor and connector. Since the conductorand connector are held together merely by physical pressure contact, arelatively poor electrical connection may be obtained. Moreover, becauseof forces being applied'to the crimped or secured mechanical connectionand perhaps thermal cycling of the connection, the pressure of theconnection eventually may become reduced to the point of perhaps beingopen circuited. Various other systems of either providing a solderconnection or a mechanical connection between a conductor and a femaletype of connector have been suggested, however, these also present allor at least some of the attendant problems as discussed above.

Another problem of presently used solder connector assemblies is that ofremoval of the connection. This is especially prevalent when highdensity female connectors are utilized. In the solder cup connector,breaking the connection is particularly difficult. With a pressureconnector the removal process is easier, however, a relativelyunreliable electrical connection is obtained.

It is therefore an object of the present invention to provide a new andimproved electrical connector assem bly and a method of providing such aconnector assembly.

It is a further object of the present invention to provide a new andimproved electrical connector assembly utilizing both a solder and apressure type of connection and a method of providing such a connectorassembly.

It is still a further object of the present invention to provide a newand improved electrical connector assembly which provides goodelectrical conductivity, ease of making and breaking the connection, andhigh reliability, and also a method of providing such a connectorassembly.

Broadly, the present invention accomplishes the above cited objects byproviding an electrical connector assembly and a method for providingsuch a connector in which an electrical conductor is soldered to afemale type of connector by utilizing in combination a pressureconnection and a solder connection. Specialized soldering ap paratus isutilized in one embodiment in order to enhance the speed of making andbreaking of the connection.

These and other objects and advantages of the present invention willbecome more apparent when considered in view of the followingspecification and drawings, in which: J

FIGURE 1 is a pictorial diagram of male type electrical conductor asutilized herein;

FIG. 2 is a pictorial diagram of one embodiment of a female connector asutilized herein; j

FIG. 3 is a pictorial diagram showing the electrical conductor of FIG. 1secured to the female connector of FIG. 2;

FIG. 4 is a pictorial diagram of an electrical conductor gripped by asoldering tool;

FIG. 5 is a pictorial diagram of another embodiment of a femaleconnector as utilized herein; and

FIG. 6 is a plan view of the gripping tip portion of the solderingapparatus as utilized herein.

Referring to FIG. 1, an electrical conductor is shown in the form of awire 10 having a portion of its insulation 12 stripped back from the endthereof. The electrical conductor is shown as a Wire having .asubstantially circular cross section, however, it may take the form ofany male type of electrical connector and may also be a single or amultiple strand structure. The exposed portion of the conductor 10 asutilized herein is tinned or solder dipped to form a solder layer 11 onthe conductor 10. The tinning process is performed in order to: (1)provide the necessary solder to secure the conductor to the femaleconnector, (2) add additional mechanical strength to the conductor, and(3) coat the ends of the conductor in the case of a multiple strand wireand prevent corrosion of the copper with the solder. In certainapplications, it may not be necessary to tin the conductor 10. However,in most instances best results will be obtained by tinning.

FIG. 2 shows a female connector 14, which is tubular in form with asubstantially circular cross-section. 'The female connector 14 may befabricated, for example, of a spring type of material which is tubularin cross-section, a counterbored rod or a formed stamping. The femaleterminal 14 has an inside diameter D, substantially identical orslightly smaller than the diameter D of the conductor 10. Two slots 16and 18 are cut from the open end 20 of the terminal 14 on opposite sidesof the terminal in a plane containing the axis of the terminal. I Theslots 16 and 18 may be formed by machining, stamping, or other methods,and are cut from the open end 20 a distance at least several times thediameter of the terminal toward the back portion of the connectorterminal. At the end 20 the terminal 14 flares out at a flange portion22 which permits the ready insertion of the conductor 10. Also theflange portion 22 provides a camming surface to the end 24 of theconductor 10 which will force apart the sides of the slots 16 and 18 asthe conductor 10 is inserted into the opening 20.

To secure the conductor 10 to the female terminal 14, the conductor 10is forced into the opening 20 with the end portion 24 thereof engagingthe flange portion 22 of the terminal 14. This forces apart the slots 16and 18 with the conductor 10 then being forced to its desired insertionlength into the terminal 14. A reactive force will be asserted againstthe conductor 10 by the terminal 14 since the inside diameter D, of theterminal 14 between the inside wall, is originally, without insertion ofthe conductor 10, substantially the same or somewhat smaller than thediameter D of the conductor 10. Thus, a pressure connection will beestablished between the inside wall of the terminal 14 and the wireconductor 10. The spring pressure also serves to ensure a very PatentedJan. s, 1961 thin solder interface between the inside of the connectorand the outside of the conductor. The connection process is completed byapplying heat to the connector terminal 14 and the conductor 10 in asufiicient amount to melt the solder layer 11 that had been previouslyapplied to the exposed end of the conductor 10. The solder will thusmelt by the well known soldering process and will adhere to the insidewall of the conductor 14 to form an excellent electrical and mechanicalconnection thereto.

The heat to melt the solder may be supplied by a conventional solderingtool or more favorably with resistance soldering apparatus whereby theworkpiece is heated by the flow of current therethrough. Such resistancesoldering apparatus is described in copending application Serial -No.358,439, filed April 9, 1964, and assigned to the same assignee of thepresent application. The use of resistance soldering apparatus will bediscussed in more detail with reference to the embodiment of FIGS. 4 and5.

Considering now the embodiment of FIGS. 4 and 5, the electricalconductor of FIG. 4 is substantially the same as that of FIG. 1 havingan electrical conductor with the insulation 12 stripped back from theend portion thereof. FIG. 5 shows the female terminal 14 beingsubstantially the same as that of FIG. 2 except that the slots 16 and 18have a widened frontal section 30 and 32, respectively, which extendfrom the front portion 20 approximately half way back the length of theslots 16 and 18. The normal unstressed inside diameter D, of the femaleconnector terminal 14 is again designed to be substantially the same orslightly smaller than that of the diameter D of the conductor 10. Thewidth w of the portions and 3-2 of the slots 16 and 18 is designed toaccommodate the tip portion of a resistance soldering apparatus.

To insert the conductor 10 into the female terminal 14, the conductor 10is gripped approximately at its midpoint between the end 24 and theinsulation 12 by a pair of gripping tip portions 34 and 36 of aresistance soldering tool as described in the above copendingapplication. The gripping tip portions 34 and 36 may have a contactingportion 38, as better shown in FIG. 6, which is V- shaped to act as aself-centering device as well as gripping the conductor 10. Of course,other configurations for the gripping portion 38 may be utilizeddepending upon the particular application. The gripping tip portionshown in FIG. 6 has such a cross-sectional dimension to permit passagethrough the portions 30 and 32 of the slots 16 and 18, and thus must besomewhat smaller than the width w, shown in FIG. 5.

With the gripping tip portions 34 and 36 gripping the conductor 10, theconductor 10 is inserted into the opening 20 of the female terminal 14.The front portion 24 ofthe conductor 10 engages the flange portion 22 ofthe terminal 14, which acts to permit the ready entrance of the terminal10 and also as a cam'ming surface to force the slots 16 and 18 apart.The conductor 10 is then inserted into the terminal 14, the gripping tipportions 34 and 36 being so aligned to enter into the widened portions30 and 32 of the slots 16 and 18 respectively. The conductor 10 isforced into the female terminal 14 until the tip portions 3-4 and 36engage the back portions 40 and 42 of the slots 16 and 18. At this time,the resistance soldering apparatus is energized which will cause currentto flow through the tip portions 34 and 36 and the conductor 10 whichwill heat the conductor 10 and the female terminal connector 14 to meltthe solder 11 which had previously been applied to the conductor 10 asdescribed above. The melted solder will adhere to the inside wall of thefemale terminal 14 and provide a good electrical and mechanicalconnection thereto. Moreover, a good pressure connection will beprovided by the cantilever action of the female terminal 14 pressingagainst the outside surface of the conductor 10.

The use of the resistance soldering tool provides a highly localizedheat in a short time. The conductor 10 is gripped at substantially itsmidpoint in order to have a relatively equal distribution of heat ineach direction without excessive heat being applied to the insulatorportion 12 of the conductor. After the soldering process has beencompleted, which will be a relatively short time because of the rapidaction of resistance soldering techniques, the soldering apparatus isdeenergized and the gripping portions 34 and 36 removed from theconductor 10 out and away from the portions 30 and 32 of the slots 16and 18.

As in the embodiment of FIGS. 1, 2 and 3, the embodiment of FIGS. 4 and5 provides a highly reliable con nection having a large contacting areausing a combination of pressure and solder connection. The amount ofsolder surrounding and connecting the conductor 10 to the inner surfaceof the female terminal 14 is relatively small to avoid the problem ofvoids or pockets in the solder. Moreover, the time necessary to make theconnection is relatively small, particularly if resistance heating isemployed.

In the embodiment of FIGS. 4 and 5, a one-hand soldering process can beemployed by inserting the wire with the gripping ti-p portions 34 and 36into the female terminal 14 and then energizing the soldering apparatus.This method is particularly advantageous when the terminals are closelyspaced together at the rear portions of a connector array. If it isdesired to remove the conductor 10 from the female terminal 14 all thatis necessary that the gripping portions 34 and 36 be inserted throughthe slots 30 and 32 to engage the conductor 10. Then, the resistanceheating apparatus is energized to melt the solder. The conductor 10 isremoved from the female connector terminal 14 with the gripping portions34 and 36 passing through the portions 30 and 32 of the slots 16 and 18.It should also be noted that in the embodiment of FIGS. 1, 2 and 3, aremovable structure is provided by heating the fem-ale terminal 14 witha suitable soldering tool and then removing the eonductor 10 when thesolder has melted.

The embodiments described above have pre tinned or solder-coated theconductor '10 before insertion into the female terminal 14. However, ofcourse, other methods of providing the solder material could beutilized. In particular, if the female terminal is a formed stamping,the inside surface of the stamping itself could be solder coated. Also,as another alternative, the conductor 10 could have a solder foildisposed therearound.

Although the present invention has been described with a certain degreeof particularity it should be understood that the disclosure has beenmade only by way of example and that numerous changes in the details ofcon struction and fabrication and the combination and arrangement ofparts, elements and steps of the method may be resorted to withoutdeparting from the scope and the spirit of the present invention.

We claim as our invention:

1. A connector assembly to be secured with resistance solderingapparatus having a gripping tip portion, said assembly comprising, amale conductor, a female connector including a pair of elongated slotsoppositely disposed thereon in a plane and extending through an open endthereof at which the male conductor is to enter, said pair of slotshaving a wider width portion at the open end of said femaleconnector-compared to the rest of the slot, said wider width portionextending a predetermined length along said slot, an abutting portionbeing defined in said slot at the end of said wider width portion, saidwider width portion being large enough to receive the gripping tipportion of said resistance soldering apparatus, solder disposed at thedesired connection area, said male conductor being inserted into saidfemale connector by grasping said male conductor with the gripping tipportion of said resistance soldering apparatus, the gripping tip portionpassing through the wider width portion of said slots in said femaleconnector and when the gripping tip portion abuts said abutting portionof said slots said resistance soldering apparatus being energized tomelt the solder to secure said male conductor and said female connector.

2. A connector assembly to be secured with resistance solderingapparatus having a gripping tip portion, said assembly comprising, amale conductor being predipped in solder for physical strength and forproviding solder at the desired connection area, a female connectorincluding a pair of elongated slots oppositely disposed thereon in aplane and extending through an open end thereof at which the maleconductor is to enter, said female connector having such a diameter sothat with said male conductor being inserted therein said slots beingforced apart to insert a force against said male conductor, said pair ofslots having a wider width portion at the open-end of said femaleconnector com pared to the rest of the slot, said wider width portionextending a predetermined length along said slot, an abutting portionbeing defined in said slot at the end of said wider width portion, saidwider width portion being large enough to receive the gripping tipportion of said resistance soldering apparatus, said male conductorbeing inserted into said female connector by grasping said male memberwith the gripping tip portion of said resistance soldering apparatus,the gripping tip portion passing through the wider width portion of saidslots in said female connector and when the gripping tip portion abutssaid abutting portion of said slots said resistance soldering apparatusbeing energized to melt the solder to secure said male conductor andsaid female connector.

3. A method of making an electrical solder connection with solderingapparatus between a male conductor and a female connector having atleast a pair of elongated slots disposed thereon and extending throughan open end thereof at which the male conductor is to enter, said methodcomprising the steps of: providing solder at the desired connection;grasping the male conductor at the opposite sides thereof with agripping tip portion of the soldering apparatus; inserting said maleconductor into said female connector with said soldering apparatus;passing said soldering apparatus while grasping said male conductorthrough said slots a predetermined distance; and energizing saidresistance sol dering apparatus to melt the solder and secure said maleconductor and said female connector.

4. A method of making an electrical solder connection with solderingapparatus between a male conductor and a female connector having atleast a pair of elongated slots oppositely disposed thereon andextending through an open end thereof at which the male conductor is toenter, said method comprising the steps of: providing solder at thedesired connection; grasping the male conductor at the opposite sidesthereof with -a gripping tip portion of the soldering apparatus;inserting said male conductor into said female connector so that theslots thereof are forced apart to apply a reactive force to said maleconductor, the slots being lined up with the gripping tip portions ofsaid soldering apparatus; passing the gripping tip portions of saidsoldering apparatus while grasping said male conductor through saidslots a predetermined distance; energizing said soldering apparatus tomelt the solder and secure said male conductor and said femaleconnector; deenergizing said soldering apparatus; and disengaging saidsoldering apparatus from said male conductor.

5. A method of making an electrical solder connection with resistancesoldering apparatus between a male conductor and a female connectorhaving at least a pair of elongated slots oppositely disposed thereon ina plane and extending through an open end thereof at which the maleconductor is to enter, said method comprisin the steps of: providingsolder at the desired connection; grasping the male conductor at theopposite sides thereof with a gripping tip portion of the resistancesoldering apparatus; inserting said rnale conductor into said femaleconnector so that the slots thereof line up with the gripping tipportions of said resistance soldering apparatus; passing the grippingtip portions of said resistance soldering apparatus while grasping saidmale conductor through said slots a predetermined distance until saidgripping tip portions abut against a portion of said slots; energizingsaid resistance soldering apparatus to melt the solder and secure saidmale conductor and said female connector; deenergizing said resistancesoldering apparatus; and disengaging said resistance soldering apparatusfrom said male conductor.

6. A method of making and breaking an electrical solder connection withresistance soldering apparatus between a male conductor and a femaleconnector having at least a pair of elongated slots oppositely disposedthereon in a plane and extending through an open end thereof at whichthe male conductor is to enter, said method comprising the steps of:providing solder at the desired connection; grasping the male conductorat the opposite sides thereof with a gripping tip portion of theresistance soldering apparatus; inserting said male conductor into saidfemale connector so that the slots thereof line up with the gripping tipportions of said resistance soldering apparatus; passing the grippingtip portions of said resistance soldering apparatus while grasping saidmale conductor through said slots a predetermined distance until saidgripping tip portions abut against a portion of said slots; energizingsaid resistance soldering apparatus to melt the solder and secure saidmale conductor and said female connector; deenergizing said resistancesoldering apparatus; disengaging said resistance soldering apparatusfrom said male conductor; re-engaging said male conductor through saidslots with said resistance soldering apparatus at any subsequent time;energizing said resistance soldering apparatus to melt the solder;deenergizing said resistance soldering apparatus; removing said maleconductor from said female connector with said resistance solderingapparatus; and disengaging said resistance soldering apparatus from saidmale conductor.

References Cited by the Examiner UNITED STATES PATENTS 2,691,771 10/1954Burtt et al 339-275 X 2,810,893 10/1957 Hidde Nijland.

2,845,516 7/1958 Jones 339275 X 3,100,330 8/1963 Rice et va1. 29502 X3,136,032 6/1964 Berndsen 29-15555 X EDWARD C. ALLEN, Primary Examiner.P. TEITELBAUM, Assistant Examiner.

3. A METHOD OF MAKING AN ELECTRICAL SOLDER CONNECTION WITH SOLDERINGAPPARATUS BETWEEN A MALE CONDUCTOR AND A FEMALE CONNECTOR HAVING ATLEAST A PAIR OF ELONGATED SLOTS DISPOSED THEREON AND EXTENDING THROUGHAN OPEN END THEREOF AT WHICH THE MALE CONDUCTOR IS TO ENTER, SAID METHODCOMPRISING THE STEPS OF: PROVIDING SOLDER AT THE DESIRED CONNECTION;GRASPING THE MALE CONDUCTOR AT THE OPPOSITE SIDES THEREOF WITH AGRIPPING TIP PORTION OF THE SOLDERING APPARATUS; INSERTING SAID MALECONDUCTOR INTO SAID FEMALE CONNECTOR WITH SAID SOLDERING APPARATUS;PASSING SAID SOLDERING APPARATUS WHILE GRASPING SAID MALE CONDUCTORTHROUGH SAID SLOTS A PREDETERMINED DISTANCE; AND ENERGIZING SAIDRESISTANCE SOLDERING APPARATUS TO MELT THE SOLDER AND SECURE SAID MALECONDUCTOR AND SAID FEMALE CONNECTOR.